Related Experiment Video
Updated: Feb 14, 2026
Synthesis of Soft Polysiloxane-urea Elastomers for Intraocular Lens Application
Published on: March 8, 2019
Synthesis and evaluation of a novel urea-based 68Ga-complex for imaging PSMA binding in tumor
Zhihao Zha1, Karl Ploessl1, Seok Rye Choi1
1Five Eleven Pharma Inc., Philadelphia, PA 19104, USA; Department of Radiology, University of Pennsylvania, Philadelphia, PA 19104, USA.
Introduction:
Prostate specific membrane antigen (PSMA) is a well-established target for diagnostic and therapeutic applications for prostate cancer. It is know that [68Ga]PSMA 11 ([68Ga]Glu-NH-CO-NH-Lys(Ahx)-HBED-CC) is the most well studied PET imaging agent for detecting over expressed PSMA binding sites of tumors in humans. In an effort to provide new agents with improved characteristics for PET imaging, we report a novel [68Ga]-Glu-NH-CO-NH-Lys(Ahx)-linker-HBED-CC conjugate with a novel O-(carboxymethyl)-L-tyrosine, as the linker group.
Methods:
Radiosynthesis was performed by a direct method. In vitro binding and cell internalization of [68Ga]10 was investigated in PSMA positive LNCaP cell lines. Biodistribution and MicroPET imaging studies were performed in LNCaP tumor bearing mice.
Results:
In vitro binding to LNCaP cells showed that natGa labeled O-(carboxymethyl)-L-tyrosine conjugate, [natGa]10, displayed excellent affinity and specificity (IC50 = 16.5 nM) a value comparable to that of PSMA 11. In vitro cell binding and internalization showed excellent uptake and retention; [68Ga]10 displayed significantly higher cellular internalization than [68Ga]PSMA 11 (12.5 vs 7.4% ID/106 cells at 1 h). Biodistribution studies in LNCaP tumor-bearing mice exhibited a high specific uptake in PSMA expressing tumors and fast clearance in normal organs (19.7 tumor/blood; 20.7 tumor/muscle at 1 h after iv injection). MicroPET imaging studies in mice confirmed that [68Ga]10 displayed excellent uptake and distinctive tumor localization, which was blocked by iv injection of a competing drug, 2-PMPA.
Conclusions:
The preliminary results strongly suggest that [68Ga]10 may be promising candidates as a PET imaging radiotracer for detecting PSMA expression in prostate cancer.
Related Concept Videos
01:23Urea Cycle
02:18The Equilibrium Binding Constant and Binding Strength
00:49Ligand Binding and Linkage
01:15Dehydration Synthesis
Dehydration synthesis (also called a condensation reaction) is the chemical process in which two molecules covalently link together to form a new molecule, along with the release of a water molecule. Many physiologically important compounds form by dehydration synthesis reactions, such as complex carbohydrates, proteins, DNA, and RNA.
Synthesis of carbohydrates
Sugar molecules are covalently linked together by dehydration synthesis. During the reaction, the hydroxyl (-OH) group from...
02:17Synthesis and Decomposition Reactions
02:36Transfer RNA Synthesis
Each of these chemical modifications is carried by a specific enzyme, post-transcription. All of these enzymes have unique base and site-specificity. Methylation, the most common chemical modification, is carried by at least nine different enzymes, with...